Testing apparatus



J. WICKS TESTING APPARATUS Filed Sept. 29, 1930 May 24, 1932.

FROM ZINE 5W FPOM T011 80 Jul-m wicks usrA'r-s I T EN CIATEI) ELECTRICLABORATGRIES,INC., OF CHICAGO; ILLINOIS, A CORPORATION OF DELAWARE rTEsTiNGAPrARe'rus Application filed September 29,'193l). Serial 80.484944. i

This invention relates to testing arrangements 1n general, particularlyto testing arrangements vfor use 1n automatic telephone SYS'CQIHS'flIlClis concerned primarily with im-- 5 proved apparatus and j c1rcu1ts forextending a connection from a test switchboard'to a subscribers lineterminating in an automatic s s accompanying single figure of drawing. 1In the drawing-theregis shown by means oif'the usual circuit diagrams,the embodiment of the invention inatelephone system in'which ;eXchange.

In systems of the above type routine tests 11) on subscribers lines areordinarily made at a central test switchboardor wire chiefs testv desk.Special test trunks extend from the switchboard to each exchange in thesystem, and each exchange is provided with a special 15 test switchtrain for extending'connections to the subscribers line. A clearmetallic circuit free of bridges andother connections is reouired fortestin pur oses. Thisis the l A r main reason for providing the specialtest switch train, as the regular. exchange switcli-- 121g apparatusordlnarlly used isnot adapted to provide such a circui Testing systemshave been,v proposed in which test connections are extended, in part,over the I exchange switching apparatus. Heretofore systems of this typehaverequired changes and modifications in" theexchange switchingapparatus in order to provide a circuit that is suitable for testingpurposes. Such arrangements are objectionable due to the increased costand to the added difliculties in maintaining the equipment.

An object of the present invention is the provision ofan improvedarrangement whereby test connections may be extended in part overexchange switching apparatus such as is ordinarily provided for localand toll service without requiring any changes or modifications whateverin such apparatus; This object is attained by providing a simple testselector adapted to operate with the standard test switchboard circuits,the selector being grouped with the regular battery feedingselectors ofthe exchange and having access in' .more complicated I or in a differentofiice.

common with these switches to the interme (hate selectors and connectorsof. the eX- change: 1.

circuits involved,"reference being had to the talkingbattery is fed froma selector in both local and tollconnections. A telephone sys- September28.1929. 1 It will-be appreciated JOHN WICKS, or 0A2: PARK, ILLINOIS,AssienoR, BY MESNEASSIGNMENTfiTO AssoQ The various featuresYo-f the,invention will i .be describedin detail in connection With-thedescription, of the 7 operation of "the ivarious that the invention maybe. employed equally 1' Well to'systemsin which talking battery is 1930to'Tharp and Wicks.

Referring now to the drawing, test cord TC, of which only 'a-parti's-showmmaybe similar to-the test cord disclosed inUnite d StatesPatent No. 1,691,269 to iCrockenof sociated with the usualtesting'devi'ces; in

'dicated infth e drawing by a" dotted line, and

is adapted to connect with test trunks, such as the-one extending fromthe. m

associatedlwith the trunkline. and are loto test selector TS, whichincidentallvmay pied from the connector in-localiconnections and from aselector in tollc0nnections, such for example as the system disclosedin'United States Patent No. 1,786,04Ll ,"granted Dec, 23,

November'l 3, 1928. .The cord circuitisasanual jack a 'J to testselector'TS. jTrunlrrelays TR are be located in the same-ofiiceas thetest desk I The test selectorto gether with local'selectorrepeaters,such as the selector repeater-SR, and toll transmission selectors,suchas the selector TTS, have access to intermediate selectors of whichone, namely, selector shown. The inter- 9 7 v 'mediate selectors in turnhave access to the various connectors of the system, such as connector Owhich has access to different subscribers lines including that extendingto substation T; 'It will be noted that the test selector is arranged toconnect with the inshown only in skeleton form since these switches maybe exactly the same as the corresponding switches shown: in fithe'zpreviously referred to Wicks application; Serial No.

By way of"illustration the operations involved in extending a connectionf-romgthe testiswitchboard to'the subscribers line ter- 925."in'in'ating' in substation l will now be described; Pl-u'g lP, (if-thetest cordTC is inserted in thejjackof an idle trunk for example, jackll,whereoncontacts 27 close and completeyacircuit forrelay 4. f-"Relay 4:,op-

' crates, closes a point "i-n the control circuit -at' contacts' 21"andprepares aholding circuit for itself in series-with relay 3 atcontacts 20. "'Rlay'lpf thetrunk circuit operates over a V circuit extending byway of thesleeve offlthe fjae'lr'andplu'g, resistance 6, togroundat contactsQG. '"Relayl' on operating completes a llocpi circuitfor operating relay 33 of the test select'orfby closing contacts10,-and'by open-- 'ing-"conta-cts Tand I1 -and*closin'g contacts 8 P and12,"the tip andring-springsof the jack are disconnected from the controlconductors and: connected .to the test conductors of the trunk.Referring'nowto-test selector,relay 33 operates "over the previouslydescribed 4 loop which includescontacts' 21 and conducftors 29 and 3Ecompletes a 'circuit"fro1n groundat" con tacts- 55, winding of relay34:, windings of "relay 35 to battery, and in 1 parallel therewith"through release magnet contacts, contacts '79, winding of verticalinagnet-40, toba ttery. Relay 33 also closes a circuit "for {relay 36byway or contacts "52566 and 74, resistance 48, to ground. *Relay 34:

operates; but due "to its relatively high re- *sistance; neither thevertical -i'ma gnet nor relay 35 operate at this time. 'Relay'34'connects ground-to the local holding "circuit at V 1 contacts-56prepare's' the 'impul'sin gcircuit at contacts "5' 7,andopensthe-releasehiagnet 'circuit'at contacts 58.; iRelay 36 nowopcrates and opens "a point in the circuit of 'r'layF37 at contacts'62;v

'The foregoing operations take "placef'responsiveto the'insertion ofthe'plug of a test it cord into thejack'of'an idle trunkline, The

mom;

wire chief will now dial the first digit of the number designating thewanted line. When the calling device CD is turned OE-normal,

contacts 14': close and complete a circuit for relay 5. Relay 5,operates, disconnects the ring and tip conductorsof the cord circuit'from the testing apparatus and connects them to the impulse contacts ofthe dial at contacts 23 and 25, andat contacts 26 disconnects groundtrom thesleeve ofthe plug.

Relay-1 oi the trunk circuit restoresduc to the removal of ground fromthe sleeve and switches control conductorsfl) and-32 ofthe trunk throughto the tipand ring springs-of ,thegjack. Relay-33 of the'test selectorisnow held operated over a controlloop-whi-ch includesthe impulsingcontacts 15 of the callng devlce. Calling device CD onreturningto'normalinterrupts the loopcircuit at] contacts 15 inaccordance with the number dialled, and relay 33 respends -'accordingly'by --'deenergizing' and reenergiiing. "Each time relay 39wdeenergizcs*a circu'it is closed from ground "at contacts 57, contacts54,

througlrt'hewindingsof rel'ay' 3i ,to battery,

and by'way of the release magnet contacts "and contacts '79, throughthe-wind 1g of vertical magnet 4E0 tovbattery. Both the relay "and themagnet operate under these aconditions'and the Wiperso'f the selectorareiraised one step. Relay 34 is slow to release due to its windingbeing short circuited-"at contacts L54 and "remains operated during 5impulsing, "Relay 35'also"remalns energized throughout series ofimpulses" being slow-to-release, due

'to its series connection with relay 3%. *Ait the'end ofthe series ofimpulses contactsl-t oi the 'CELllIDgIdQVKZQ' Will again open and re-*l'ay will restore thereby reconnectingthe ltest apparatusto the: ringandtip conductors pofthe'cord. Ground onthesleeve reoperates relayl andthe holding loopfor relay 33 is again closed'at 'contactsl0. In the test7 selector, relay 35 restores shortly after the last impulse oftheser1es-and, since ofi-non' mal contacts 44 have closedkon theiirstWr-*tical step of the "wipers, a CHC'Lllt .1s "C0111- "pleted'forrotarvmagnet dl 'by-way of con- "tacts '61 and 77 and interrupter contacts'8l'I/Jiagnet; 4:1 energizes, rotates the wipers one step and nterrupts itsown. circuit-at contacts "81. "This operation will "be repeated untiltest wiper 84 encounters an rdletrunk,

"which is'marked .by the presence of battery potential on the testconductor corresponding to conductor 88. When an idle trunk isencountered relay 39 w ll operate over its upper wlnding and open thecircuit of the rotary magnet at'contacts 'i'i, thereby stopp ng therotary fmovement of the QWlPG-ISf I'Relay 39 completes a'lockingcircuitfor its lower winding in series with the rotarymagnot by closingcontacts 76, and short-circuits its upperwindingat contacts 7510marh'the seized trunk line busy by "connecting direct 'groundthereto. Itwill be recalled that relay 36was energized'when the switch was seized.During the transmission of? each seriesof impulses a temporary holdlngc1r-' cui't forthe relay is completed by way of con tacts53, resistance50,.a'nd contacts 56. Upon the'operationof relay 39 the line ipers 82and 85 are connected to the control conduc-' tors'of the switch and theoriginal energizing circuit of relay 36 is opened at contacts 74:. Relay36 remains energized, however, over a wiper 85, contacts 80 and 69, togrounch The impulse relay of the 'intermediatei selector energizes inserieswith relay 36 and prepares the selector for operation.

The wire chief will now dial the next digit or" the number whereon theswitching opera,-

tionsin the cord and trunk circuits take place as forthe previousdigit.Impulsere:

lay 33 of the test seclector responds as before, and with eachdeenergization interrupts the loop circuit for the impulse, relay of theintermediate selector at contacts 52. Relay 35' again operates duringthe series of impulses buthas no effect at this time. It willbe noted,however, that the upper winding of relay 35 is now short-circuited byway of contacts 78 and the release magnet contacts.

.Thisis for the purpose of increasing. current 'za flow in the circuitof release relay 34: to insure the complete energization of that relay:1 The p the foregoing that 'thereis now 'a' clearjme- 'tallicoircuitfrom the testing apparatus at I impulse relay of the intermediateselector responds to the impulses in the usual Way and the wipers oi"the switch are' raised to the called'level Whereonthey are rotated overthe impulse relay of connector 'C which operates. V

It was previously mentionedthat the upper Wiper of test selectorTS'connected with'the upper trunk conductor whereas the upper 'Wiper ofa local selector repeater, such as SR,

connected with the lower talking conductor of the trunk. In bothselectors, battery is a connected to the upper wiper and ground to thelower wiper so that battery flow over the connection will be in onedirection in local calls andin the opposite direction intest-call's.

This arrangement isfor-the purpose of operating a polarized relay whichis connected in series with the impulse relay of the connector. Thispolarized relay on operating prepares the connector for toll operationby 65 preparing the special test circuit and by looking up thering-cutoff relay of the: con

nector to preventringing cur-rent from'belng applied to the calledfline.

The second and "third digits "tie" aw dialled. -The test'selectorrepeats these series of impulses in'the same manner as'in the'case ofthesecond series of impulses, and the Wipers of connector G are operatedinto-en ga'gement with thecontacts associatedwith the wanted subscribersli' e, that is, the line 1 comprising conductors 94'96.

It will be assumed first that the called 'line, 'is'idle at this timeand that the connector cuts in and -seizesthe[line in the usual .way.;WVhen theline is seized, the impulse relayof the connector "isdisconnected'from the control loop and loop is extended througli tothewipers ofthe'conne'ctor. It will be recalled that relay 86 of thetestselector. has been heldoperated throughout the 1 setting of theswitches, first, over alocal circuit, second, in series with the impulserelay-of the inter-' mediate selector, and last, in series with theimpulse-relay of-the connector. When the connector cuts through, theopening of the relay 37.- Relay 37 operates, completes a locking circuitfor itselfat contactsfit, and extends the control conductors of theselector control circuit permits relay 36 to release and a circuitisthereby closed at'cont'acts 62 for through to the test conductors ofthe'trunk. at contacts 67 and 68. JThe intermediate selectorand-connector are preventedfrom releasing at this time -by -gr,ound'onthe release trunk conductors applied via contacts 560i the testselector. It will be clear from I the test switchboard to thesubscribersline,

C, and wipers ofthat connector, respectively, to line conductors 94 and96. The wire chief may now apply the usual-te t to the called line overthe above circuit.- and if=desired may signalthe subscriber onthe linejby applying 'ringing'curren't to the test circuit V V. l 20 Itmay happenthat thefwire chieffindsit H necessaryfto attend to "other matters andat g at the cord.

thesame time is desirous of holding-upthe connectionpreviouslydescribed. In this case n t is only necessary to withdraw-theplu'gfrom the jackwhereon contacts. 27=-wil'l open and remove theshort-circuit from" relay 3.-1Relay j 3 "will operatein: serieswith-relay e' which remains operated, and1.a;holding circuit is Ivclosed for impulse relay 33 0mm test'selector 3 i -at'zcontactsll6.:;Relay;-3rals'o prepares asuperivi'soryccircuit r by :.connecting{ground to test conductor 30 at"contactsr17 and ?battery' throughrelay-2 toate'stconductor -31 at con- ::tacts l9. --':Should thesubscriber on. the called lineaat'tempt to makea call at this time, the

, wirex chief.v

' 7 *When it is desired-to release the connection .theplug is withdrawnfrom the jack=whereon ithe soperations above described :take place.

. KeyK;is-thenactuatedto close contacts 28 thereby shunting .relays 3and -4-vvhich re- :store. Relay 3 on restoring opens the holding Eloopatcontactsll6 and disconnectsthe-super- -:visory; relayifrom: testconductor 31. Relay 4 opens itscwn holding circuit at contacts 20.

- IRe-lav 33 .ofthe test selector restores and contacts591and7lconnectsbattery via resist- ..ance 14:6 to: the; conductor.instead. The .value ofresistance-46 is suchothat the wiper closingrelay. ofthe connector willoperate and switch .the connection through inthe :usual way.

- isz-now closed byway of'o'ii normal"springs .--shortly. thereafter,relay'34 restores. A circuit 43 which closed=on the first vertical stepof 'the wipers,=-contac'ts 58, winding of release magnet-42 -'to 7battery. The; release magnet operates in the usual way 'to restore thes'witch wipers tonormal position. r'l here- -lease-ofrelay 34c-alsoremoves ground from .thei'release .trunlr-conductorat contacts 56thereby permitting intermediate-selector I-S iandconnectorC to. restorein the usual way. 7 .In the foregoing connection it was aszsumedathatidle-switches were avail-able for extending the connection' asdesired."In case -no idle intermediate selector is available H and --areoperated, the former connecting :the usual busy tone totrunk conductor:29 to inform the wirechief that all'trunks are busy.

. :The closure ofjcontacts45co1npletes an operating circuitfor relay 39extending by Wayo'f contacts 145- and the winding of'vertical' mag-'net-AOtO-battery. .Relay"38operates-and 250 :opens the circuitof therotary magnet at conit-aots 7 7-and connectsgmagnet A1 in parallel-With-magnet- LO. It maybe' noted,.however,

:that due to the relativelyhigh resistance of .-'relay- .39, neither therotary -.magne,t= nor the vertical magnet will operate in series withtrelay 39. The wire chief oninoting the busy tone is expected toreleasethe connection as previously described.

jso

. When an intermediate selector encounters an all trunks busy condition,substantially :the same operations take place although in this case thebusy tone is applied to the board,': a train of-automatic switchesflfor:extendinga connection from the switchboard to a subscribers line, ;a'ifeeding bridge in ithe ftrunk 'i rom the I intermediate selector. Thecircuit of rel'ay 36.:is opened, of .course',-; and "Lt-his :relay:restores and i permits zswitch-tover the usual manner.

relay-f371to operate Ethereby transferring-the reconnection tothetest.conductors ofthe .trunk so that the {busy 1 tone isxstransmitted xthere-.OVQI'. I r" r Whenuthe;connectorencounters ail-inc busy.inwanothericonnectionthe wiper closing relay of the-connector will beconnected infacircuit including control conductors :91. and .87 'w i per:83 of the test selector, contacted-6 0,. resistance as, winding ofrelay 38 :to battery. .ERelay 38 -willoperate this circuit: but due toresistance A9, the wiper 5 closing relay of the connector does "not.operate atthis time. :ZRe-

l lay 38' applies busy: tone to trunk conductor -29 at contacts-7=0 and.at contacts 'ZZcompIetes can noweilecta connectionwith .thebusy line bydialling'an. additional digit. .Rel'ay133of :the testselector respondsin: the usual =way; to

this additional digitandrrelay 35 alsooperates. Relay? 35 onoperatingrdisconnects relay 38 from. the. control" conductor andbywayiof The-impulsemelayofthe connector will be as previously described.vTheline conductors *arenowextended oven-the test conductors of the.trunk. to. the testing apparatusrat the .test

switchboard-to which .the op erators telephone set may :beconnectedasdesired. The wire .chief canthen'flisten-in to determine whether i ornot the lineisibusy in a connection orwhether it is beingheldnup' duetoearfault. If the line is engaged in another connection @the wire chiefmay eifect the release thereof byflapgplying ground to iboth testconductors of. the

trunk.- This; ground operates adifierentia'l relay in thelocal selectorrepeater engaged f in the connection with the busy line, this relaycausing "the selector repeater and other switches. involvedto release inwell-known usual itests to the line after 1' having the sexchangeattendant release the line switch in that is claimed is I 1. In atelephone system, a *test switchboard, a train of automatic. switchesfor: ex-

tending. a connection from. the'switchboard to a subscribers line, azfeedi'ngbridge in the firstswitch of. the trainforfeedingbattery in thedirection of the .calledline, and auto- :matic means for disconnectingsaidbr-idge and for establishing a clear metallic circuit 2. In atelephone system, a test switchllclisconnected .as usual and theswitchover I operation inthe: test-selector "will takegplace manner. TheWire'chief can then-apply the first switch of the train-for feedingbattery in the directionof the called line during the setting of theswitches, andmeans responsive to V the completion of the connection withthe tablishing a clear metallic circuit between the switchboard andtheline. a v p 3. Ina telephone system, a test switchboard, a'trunk linecomprising operating conductors' and test conductors terminating in theswitchboard, automatic switches means controlled from theswitchboard foroperating said switches to establish a connection with a subscribersline independent of said 7 test conductors,and means responsive to theestablishment of the connection withsaid line for including said vtestconductors in the connectiom V 7 .4. In a telephone system,atestswitchboard, a test selector, other automatic switches-means,controlled from the switchboard for operating saidjselector and saidother switches'to establish a clear metallic circuit between theselector and a subscribers-line, and automatic means responsive to theestablishment. of a connection with the line for extending said circuitthroughvto the switchboard. v v 4 5. In a telephone system, a testswitchboard, a test selector, other automatic switches, a trunk linecomprising operating conductors and test "conductors extending fromtheswitchboard to said selector, means controlled over said operatingconductors for 5 operating said selector and said other switches tocomplete a clear metallic circuit between the selector and a subscribersline, and automatic means including a relay controlled by said otherswitches for connecting said circuit to said test conductors. 1

board, a trunkline comprising operating con-j ductors and testconductors, va test selector and a connector, meansicontrolled over saidoperating conductors for operating said selector to seize saidconnector, a control'circuit extending from the selector to theconnector, means in the selector controlled over '1 saidoperatingconductors for interrupting said circuit to transmit digitllimpulses, arelayin the connector responsive tosaid impulses for; setting theconnector on a subscribers line, and meansin the selector responsive tothe connector engaging 'sai'dline for extending the .controlcircuittothe test switchboard viasaid test conductors.

board, a trunk line comprising operating conductors and testconductorsfa test selector and a connector, means controlled over saidoperating conductors for operating sa d selector to seize connector, acontrol circuit ex-" of current to said. circuit, means in the se-' theconnector responsive to said impulsesforline for disconnectingsaidbridge and for es- 1 "pleting a test connectioncomprisin'g a clear,6. In a telephone systelnya test switchhb r and a subscribers lectorcontrolled .over said operating conductors for interrupting said circuitto trans mit'di'git' impulses over the circuit, a relay 1n selectorrepeater and a connector for complete ing a talking connection'betweentwo sub-,-

scribers lines, and means including another;

selector repeater and said connector for com- 30 metallic circuitifreeofbridges and branch connections from said switchboardfto a sub 1scribers line.- r y 1 c 9, In a. telephone system, a test switch;board,a toll switchboard, means including a, I. SGIGCtOIIBPGatQIEaIld aconnector for extend-1 ing a talking connection from ls'aid t tollswitchboard to a subscribers line, "and means including another selectorrepeater and said,

tion between two subscribers" lines, means, iinc'ludinga toll selectorrepeater and said connector for com'pletinga talking-conne'c' tionbetween said toll switchboard and a subs'cribers li'ne, an'dineansincluding a 'testsee lector repeaterand said connector for completingfatest conne'ction between said tests lllIn a telephonesyst'em, a selector're peater," a j trunk line' comprising operating conductorsand'testcon'ductors terminating p in said selector repeater, atrunklinleinclud- ,ing operating conductors accessible to said selectorrepeater, meanscontrolled over the operatingconduotors ofsa'id firsttrunk line" for operating said selector repeaterf to ,con- I p V nectwith said second trunk line and forthenl transmitting impulsesovertheoperatingconductorsjof'saidsecondtrunk line to extenda connectionto a silbscribers line, and means 1 I i theselecto r grepeater forconnecting the operating conductors or" said second :trun'k n linedirectly to the'test conductorsofsaid u i 7. In a, telephone system, atest. switchfirst trunk line,

' 12. Ina telephone system, al 'selectorire b I lector repeater, meanscontrolled overfthef operating conductors of saidfirst trunk line foroperatingsaid selector repeaterto'jc'onnect a i! ,connector'iorcompleting a test connection.

in said selectorrepeater,agtrunklineinclude I .ing operatingconductorsaccessible to saids'ea with said second trunk lines and: for then:transmitting impulses-over the operating 0.0a ductorstof saidfsecondtrunk line, to extend the: same into iconnection with aisubscribefls;

line, and means responsive to, the establish mentiof sald connection forconnecting then. operat ng conductors of saidsecon-ditrunki' line"directly to the itestr conductors. of saidi first trunk line. V 1

"13. Ina telephone system, an. automatic switch, a trunk line comprisingtwo-pairs of V conductors terminating-in said 'switch, asecnd trunk lineincluding a pair of conductoirs accessible to said SW1tCh,' meanscontrolled over one pair of conductors of sa d lirsttru-nk line foroperating said switch-to connectwitlr;

said second trunk line, means-insaidswitch iorconnecting abridge-acrossthe conductorsofsaid second trunk line and for inter-rupt ing saidbridge to transmit-impulses over the,

second trunk line whereby the second trunk line is extended'intoconnection with a subscribers line, and means in said'switch forconnecting the other pair of conductors of said first trunk line to thecond-uctor's of said second'trunk'line in place of said bridge.

- lh'In a telephone system, an automatic switch, a trunk linecomprising, operating conductors and test conductors terminating in saidswitch, a trunk line; including opera ating'conductors accessible to 1said switch, means controll ed 1 over the operating con u t r f s rst tn ne e con r in said SWltChf tO connect with said secontl trunli lineand for then transmitting impulses oyer the operating conductors of'saidsecondjtrunk l ne t ico ne s i asubscribie'rfs e, n s aid wit lll ispbnsive. en thesubscribers lineis busy for' applying ai 1 id-firstlllsc i s adflie fi in a w v rs p siye whe the ubssr h fl ,l ss

- trunk line including operating conductors sh le or nn t l gl' hsisretingt on: et rs bfj id S o d trunkfie iretlyi the I operatingconductors of said {first ,trlink line. J

5-; a e P Qns y tem, first ut mati wit h; e nd woman sw tc r atr nk lie; Co p isi g bpfi fi l gO QWIS IIdW31 nduc o s i min'at gifi aid rst sehia rminetingi Said. second sw t im ans, C011,;

' r dl i h pe ating. ductersbfs id line for completing adirect'connecti-on be tween the operating conductorsof said secondtrunkline and the test conductors of -said'fi-rst trunk-line. i i 1 I16; In a telephone, system, automaticswitches, a trunkv line comprising.two ipalrst of conductors. terminating in; onelofasaidl V switches,meanscontrolled oyersthe. firstzpair; ofconductors of saidtrunklineffor. setting '7 said-one switch, a .rela'yein said one switcl-renrergized over a local 1 circuit; during the-sets tingofi the switchandoverianrexternal circuitextending to a succeeding switch-at thecompletion of the. op'erationof said: one:

switch, means. in said-one switchacontrolled; over the first 7 pan: ofconductors "of; said trunk. line for transmitting impulses; over,

said externali circuit to set: saidsucceeding switch, m'eans foropening'said eXternalsci-r cuit at. the completionoi' the operationiofsaid succeeding switchito deenerg'ize said zres.

lay, and means responsive to the deenerglizas tion of said relay.ifor;connecting the second pairloficonductors of:said trunk line to saidexternal :circuit'in1placesofsaid relay: 17. In a telephonehsystem," a;-trunksli'ne.

comprising. two operating: conductors andtwo. test conductors,saidioperating-icondud:

' tors normally terminatinglin'the springso-f a .manual jackiat: oneend-and inrthelimpulse relay-..of an 'automaticswitch at the other endand said test conductors being normally open at both .ends,meansa-responsive to the establishmentdof a connection with said trunklineivia said jack, for-connectingsaid test conductors to. the. jacksprings: in: place ot said operating condiactorsand fen closing a.bridged across,- said/ operating conductors to operate saidimpulserelay, means; controlled over saidjack for temporarily restoringthe. normal connection ofsaid 1 conductorsito th-ej acki springs; toplace said relay under control: 01- acalling ;device'-for-setting saidswitch, and means efiective aftersaid -.switch has been set forconnecting: said testconductors through-to asubscribers-line.-

18-.--In a telephone system; subscribers lines, a test switchboard,selector switches, aiconnector switch, me ans i'or operatin said--switches :to establish a talking coimectioitbe tween two subscriberslines, means for 0peratingaportioh of said selector switches and said"connector switch to establish-a test connection between= theswitchboard and a: sub; scriber s line,- and means at the-switchboardfor-measuringthe 1 electrical characteristics. of the line-over saidtest connectiom- 19.: In a telephone system, -subsori-bers lines,a tol-lswitchboai'd, -a testzswitclrboardg a train of automatic switches,meansf 'reS- tablishing a talking:-connection-;between two" subscribers"lines I over i said R switch trail-1;,

means for --esta b-lishing-' a'tal-king connection 7 between the tollswitchboard and a subscrib V ers 'li ne over'apart of said switch train;and

means for establishing a test connection betw've'en-the test switchboardand a subscriber- 's li-neover;said" part of the switeh train.

" 20. In. atelephone system, a subscribers I intermediate selector andsaid connector, and 1 line, a local selector, a toll selector, atestselector, an intermediate selector, a connector,

means for establishing an inductive connection to said line over saidlocal selector, said intermediate selector and said connector, meansforestablishing an inductive connec tion to said line over said-tollselector, said means for establishing a clear metallic connection tosaid line over said test selector,

said intermediate selector and said connector. In Witness whereof, Ihereunto subscrlbe my name this 27th day of September, A. D. a

1930. JOHN WICKS.

